FIGS. 5A and 5B are views illustrating one example of conventional two-member connection structures for working machines, in which FIG. 5A is a fragmentary cross-sectional view and FIG. 5B is a view as seen in the direction of arrow B in FIG. 5A. It is to be noted that FIG. 5A illustrates only a left half.
FIGS. 5A and 5B illustrate a connection structure for two members disposed in a working machine such as a hydraulic excavator, for example, each outboard member, e.g., a bucket 20 and each inboard member, e.g., an arm 21 arranged inboard the bucket 20. An outboard bushing 22 is press-fitted in a pin hole 20a of the bucket 20, and an inboard bushing 23 is press-fitted in a pin hole 21a of the arm 21. Inserted in a hole 22a of the outboard bushing 22 and a hole 23a of the inboard bushing 23 is a connector pin 24, that connects the two parts of bucket 20 and arm 21 for relative pivotal movement. Flange portions 25 are arranged on opposite end portions of the connector pin 24, respectively, such that the flange portions 25 are integral with the connector pin 24 to restrict slip-out of the connector pin 24 from the bucket 20 and arm 21.
Further, on an outboard side wall of the bucket 20, a stopper 26 having a recess 26a of a shape corresponding to a tapered shape of a free end part 25a of the flange portion 25 is arranged as also depicted in FIG. 5B, and on an upper wall of the stopper 26, a plate 27 or the like is secured by bolts 28. The stopper 26, plate 27 and the like make up a mechanism for restricting rotation and slip-out of the flange portion 25 and connector pin 24, in other words, a rotation and slip-out preventing mechanism for the connector pin 24. An unillustrated right half of a center line in FIG. 5A has a structure symmetrical to the left half without the rotation and slip-out preventing mechanism for the connector pin 24, said mechanism being included in the left half and being composed of the flange portion 25, stopper 26, plate 27 and bolts 28. It is to be noted that a technology equivalent to the conventional technology illustrated in FIGS. 5A and 5B is disclosed in JP-A-7-331689